Closable trays of a wide variety of shapes and sizes, configurations, etc. have been invented and offered to the market. One area of the market that employs a variety of open ended trays that are closable by one means or another, is the fast-food market, for example, the home delivery pizza market, where a closable tray (generally a tray made of corrugated board to provide insulating between the hot pizza and its surroundings) has found a large degree of acceptance.
Generally, pizza boxes are formed of corrugated board and include a bottom tray and a top cover with side walls that telescope within the side wall of the bottom tray to close the container. These are one piece containers, i.e. the top and bottom are foldably interconnected, and are generally erected on the premises of the fast-food service from a single blank immediately prior to their use.